In recent years, various techniques have been developed in the field of wireless communications, in order to efficiently utilize limited wireless resources between mobile stations and base stations. Examples of such techniques include a divided download method by which data is divided into sections so that the divided sections can be downloaded at the same time. According to the divided download method, communication resources are efficiently utilized by downloading the divided sections of data at the same time. Compared to other methods by which data is downloaded without being divided into sections, the divided download method is able to realize a data communication at a higher speed.
Patent Document 1: International Publication Pamphlet No. WO 2009/142059
According to the conventional technique described above, however, a problem arises where, when a deterioration has occurred in the communication quality during the download of the data, the progress of the download is worse than when using a method by which the data is downloaded without being divided into sections.
For example, when a deterioration in the communication quality has occurred during the download of the data due to a degradation of the communication environment or a restriction imposed on the communication volume, the throughput may decrease and the download may be timed out without being completed. When the download is timed out, according to a method by which the data is downloaded without being divided into sections, the download is resumed starting with a continuation of the data that had been downloaded before the timeout. In contrast, when the divided download method is used, the download is resumed starting with a continuation of the section of data continuous from the head among the sections of data that had been downloaded, and the other sections of data that are not continuous from the head are discarded. As explained herein, according to the divided download method, some data is discarded when the timeout occurs due to the deterioration in the communication quality. Consequently, the efficiency of the download is lower than when using a method by which the data is downloaded without being divided into sections.